Power driven impact tool



y 1955 c. T. SCHODEBERG 2,712,254

POWER DRIVEN IMPACT TOOL Filed May 14, 1955 3 Sheets-Sheet 1 3 x a J 37 15 j l J 5 av 5 g 59 44 a J 3. 49 I "i .2? J a 45 4 INVENTOR. 17 2 C421. Z 500055526,

J8 v4 22, 94 7 4 5 i W Arraewsx y 5, 1955 c, T. SCHODEBERG 2,

POWER DRIVEN IMPACT TOOL Filed May 14, 1953 3 Sheets-Sheet 2 AQL 1: Sch 0055526,

INVENTOR.

"Wm ATTORNEY.

July 5, 1955 c, T. SCHODEBERG Y 2,712,254

-POWER DRIVEN IMPACT TOOL Filed-May 14, 1953 3 Sheets-Sheet 3 CARL 56740058526,

, I N V EN TOR.

BY Z/ w I I ArTaQA/E Unite atent O PGWER DREW EN lMPACT T601.

Cari Theodore Schodeherg, Los Angelcs, Calif.

Application May 14, 1953, Serial No. 355,100

3 Claims. (Cl. S152.35)

This invention relates to a rotary tool capable of use either as a wrench or screw driver. More particularly, the invention relates to a device of this character, driven by an electric or air motor or the like, and so arranged as to provide periodic impact upon the wrench or screw driver, in the event the resistance to turning is increased. 13

it is one of the objects of this invention to provide a simple and inexpensive device of this character.

in impact tools, it is necessary periodically to store energy, such as in a spring, and to release the energy, while simultaneously the drive to the tool is interrupted and reestablished. it is another object of this invention to synchronize these steps in a simple manner, especially by the aid of a sloping groove or grooves that serve to connect and disconnect the drive as well as to store and release the impact energy.

This invention possesses many other advantages, and has other objects which may be made more ciearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming part of the present specification. The form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope or this invention is best defined by the appended claims Referring to the drawings:

Figure l is a side elevation of an embodiment of the invention, shown as in driving relation to a power device, such as an electric motor;

Fig. 2 is an enlarged view, mainly in elevation of device incorporating the invention, the casing elements being shown in section;

Fig. 3 is a longitudinal sectional view of the device incorporating the invention;

Figs. 4, 5 and 6 are sectional views taken along planes l) is shown as having a generally tubular casing 2 within I which substantially all of the operating parts of the device are enclosed. At its right-hand end the tubular casing 2 is provided with a cover 3 telescoping within the casing 2 and held in position by one or more headless screws 4. This cover has a central aperture 5 accommodating the bearing member 6 having a flange 7 resting against the inner surface of: the cover 3.

Bearing member 6 rotatably supports a shaft 8 having a reduced extension 9. This reduced extension 9 is adapted to be held in a chuck (Figs. 1 and 2) rotated by a source of power, such as a hand motor 11. The hand motor 11 may be of a conventional type operated either by electrical power, or by compressed air, and controlled by a trig er mechanism 12.

The shaft 8 is thus continuously driven by the aid of the motor 11 whenever the motor is energized.

The casing 2 has a left-hand cover member 13 telescoping within the casing 2 and held in place by one or more headless screws 14. Supported in the central aperture 15 of this cover member 13 is a bearing sleeve 16. This bearing sleeve 16 serves rotatably to support a tool member 17. This tool member 17 has a flange 18 adjoining the flange 1% of the bearing member 16. The tool member 17 has an internal bore 20 within which telescopes the reduced left-hand end 22 of shaft 8. This extension is piloted within the aperture 23 of the tool member 17. In this way the shaft 8 is adequately supported for rotation.

The left-hand extremity 24 of the tool member 17 is non-circular in cross section (Fig. 7). In the present instance it is shown as square, capable of being used as a wrench of the type adapted to be received in a socket or recess in the head of a bolt or screw.

Optionally, it may be converted into a socket wrench by the aid of an adapter 25 shown in Figs. 1 and 2. This adapter is arranged to be detachably coupled to the extension 24. For this purpose, at its right-hand end it has a square aperture into which the extension 24 fits. At its left-hand end the adapter 25 is provided with a socket wrench portion 26 adapted, for example, to engage the head 26a of a nut or bolt.

The adapter 25 is detachably coupled to the extension 24 by the aid of a spring pressed ball 27 (Fig. 2) located in a recess 28 of extension 24, and radial to the axis 29 of rotation. The upperedge of this recess 28 may be upset in order to restrain the ball 27 against removal. A spring is located in the recess 28 for urging the ball 27 into the annular groove 31 formed in the interior of the adapter 25.

During the period that the resistance to turning of the tool holding member 17 is quite low, there is a direct mechanical drive between the shaft 8 and the tool holder 17. When the resistance torque increases sufliciently this direct coupling is interrupted. Thereafter, upon continuation of the rotation of the shaft 8, an impact blow is imparted to the member 17, urging it angularly.

For this purpose, the shaft 8 carries a driving member 32. This driving member 32 is in the form of a hollow cylindrical body capable of relative rotation with respect to the enlarged intermediate portion 33 of shaft 8. The body member 32 has a running fit with respect to this 1 enlarged shaft portion or member 33. At its left-hand end this driving member 32 is provided with a relatively thick flange 34. This flange carries on its left-hand face a plurality of driving elements or projections 35. Two are shown in this instance, arranged diametrically opposite each other. These driving elements 35 project generally in a direction parallel to the axis 29 (see particularly Figs. 4 and 7). They cooperate with radially extending diametrically opposite abutments or elements 36 mounted on the flange 18 of the driven member 17.

As viewed in Fig. 4, the driving elements 35 cooperate with the elements 36 to rotate the driven member 17 in a counterclockwise direction.

The driving member 32 is continuously urged toward the left, as viewed in Figs. 2 and 3. In this way the elements 35 are urged into cooperative driving relationship with the elements 36. For this purpose a compression spring 37 is provided. The left-hand end of this compression spring engages the flange 34. The right-hand end engages a collar or washer 38. This collar 38 is in contact with the left-hand race 39 of a thrust ball bearing structure 49. The right'hand race 41 of this thrust bearing structure abuts shoulder 42 of a spacer bushing 43. The shaft 8 extends through this bushing 43.

The arrangement is such that When the shoulder 44, formed between shaft 8 and its enlarged portion 33, approaches closely to the left-hand face of the bushing 43, the shaft 8 extends for a short distance through the bearing member 6. A pin 45 passes through a diametrical aperture 46 (Fig. 7) of the shaft 8 to restrain the spring 37 in compressed condition between the collar 38 and flange 34. The spring 37 exerts a relatively large expansive force even upon a small compression thereof.

The driving member 32 is provided with exterior equiangularly spaced projections 47, 47a and 47b (see particularly Fig. 6) serving as a guide for maintaining the spring 37 substantially centralized with respect to the axis of rotation 29.

In order to rotate the tool member 17, a coupling is effected between the shaft member 33 and the driving member 32. This coupling is so arranged that when the resisting torque increases, the driving member 32 is urged toward the right, as viewed in Figs. 2 and 3, until the members 35 and 36 separate. This action also stores energy in the spring 37 since it is compressed by an amount corresponding to the width of the driving abutments or elements 35.

As soon as the uncoupling is effected the stored energy 5 in spring 37 urges the driving member 32 toward the left and the elements 35 are then urged into cooperative driving position. Continued rotation causes the abutments 35 to engage the abutments 36 whereby an impact blow is imposed upon the abutments 36.

For securing this type of drive between shaft member 33 and driving member 32, use is made of one or more oblique grooves 48 and 49 in the periphery of the shaft member 33. These grooves are of substantially semicircular cross section.

In order that the mechanism operate equally as well for either direction of rotation, both grooves 48 and 49 are formed as complete loops. The loop formed by groove 48 is oblique to axis 29, and the loop formed by groove 49 is oblique but in an opposite direction to groove 48, and the obliquities are equal.

These grooves 48 and 49 are shown to best advantage in Figs. 7 and 8. In order not to confuse the drawings, the grooves 48 and 49 in Figs. 5 and 6 are shown in planes normal to the axis 29. Fig. 8, however, shows the development of the grooves 48 and 49 upon the periphery of member 33.

The inner periphery of driving member 32 (Figs. 3 and 6) is provided with a ball seat 50 within which is seated a ball 51. that cooperates with the groove 48. It is held in groove contacting position by the aid of the headless screw 52.

Diametrically opposite to the ball 51 there is located a similar ball 53 cooperating with groove 49 (Figs. 3 and 6). This ball 53 is held in cooperative engagement with the groove 49 by the aid of a headless screw 54 located in the projection 4712.

By referring to Figs. 3 and 8 the action of the mechanism may be properly described.

As the shaft 8 is rotated (in a counterclockwise direction, as viewed in Fig. 4) the elements 35 serve to drive the elements 36 and a direct drive is effected between the members 32 and 17.

When the resistive torque increases upon tool member 17, the shaft member 33 advances angularly ahead of this tool member. The balls 51, 53 both move toward the right. At the start of this action, the balls 51 and 53 are in position a of Fig. 8. This also corresponds to the position illustrated in Fig. 3. Now as the shaft 8 continues to rotate against the resistive torque, the balls 51 and 53 move by equal increments toward the right along grooves 48 and 49. An intermediate position b of these balls is illustrated in Fig. 8. The balls 51 and 53, however, remain axially spaced by the same amount as before.

Since the balls 51 and 53 are carried by the driving member .32, the driving member 32 is urged toward the right during this action, compressing the spring 37. Energy is therefore stored in this spring.

When the balls 51 and 53 (and driving member 32) This ball 51 has a spherical surface reach a position corresponding to position c, the members 35 of driving member 32 are withdrawn to the right, out of driving relation to members 36. This position c corresponds to nearly the extreme rightward extent of grooves 48 and 49.

As soon as this occurs, the resistive torque imposed upon member 32 is greatly reduced. Angular rotation of shaft member 33 and driving member 32 continues and is ahead of the driven member 17. The left-hand surfaces of the driving projections or abutments 35 (as vicv-xcd in Fig. 2) slide over the righthand surfaces of members 36. After a small relative angular movement, the members 35 will have been moved out of angular overlap with the respective members 36. Then the force of the spring 37, operating through balls 51 and 53, and grooves 48 and 49, effects a quick advance of shaft 8, and an impact blow is effected upon the members 36 by members 35. By the time member 32 moves into a driving position, the shaft 8 will have brought the members 35 into contact with members 36. The cycle can then be repeated.

Since the grooves 48 and 49 form symmetrical loops, the same action occurs for a reverse direction of rotation.

The inventor claims:

1. In a rotary impact tool mechanism: a driven tool holding member, a rotary driving member; said members being rotary on a common axis, and having interengaging elements by the aid of which a drive may be effected, said driving member being axially movable to couple and uncouple the members; a resilient means urging said members to coupling position; a shaft mounted on said common axis and adapted to be power rotated; said shaft having a pair of axially spaced peripheral grooves each in the form of a closed loop and symmetrically oblique to the axis; and projections on diametrically opposite parts of the driving member and respectively entering said grooves.

2. In a rotary impact tool mechanism: a casing; a rotary shaft having an end extending beyond one end of the casing for connection to a source of rotary power; bearing means carried by the casing supporting the shaft for rotation about an axis; a driven tool holding member having an end extending beyond the opposite end of the casing for connection to the load; bearing means carried by the casing supporting said driven member for rotation about said axis; a rotary driving member in the casing supported upon the shaft for relative rotation with respect thereto; means for axially moving the driving member with respect to the shaft in accordance with the relative angular movement therebetween, comprising means forming a pair of axially spaced peripheral grooves on said shaft, each groove being in the form of a closed loop, the grooves being equally oblique to the said axis and symmetrically oriented with respect to a plane normal to said axis, and ball detents carried by the driving member extending respectively into the grooves, the ball detents being axially spaced from each other in an amount corresponding to the axial spacing of the grooves, the ball detents being located on diametrically opposite sides of said axis, the detents being capable of simul taneously engaging respectively those portions of the grooves located nearest the driven member to determine a limited axially advanced position of said driving member; means forming a coupling between the members separable upon a predetermined axial retraction of said driving member from said axially advanced position, comprising abutments carried respectively by the members; and a helical compression spring extending about the driving member and engaging at opposite ends, said bearing means and said driving member for urging the driving member toward said axially advanced position.

3. In a rotary impact tool mechanism: a casing; a rotary shaft having an end extending beyond one end of the casing for connection to a source of rotary power; bearing means carried by the casing supporting the shaft for rotation about an axis; a driven tool holding member having an end extending beyond the opposite end of the casing for connection to the load; bearing means carried by the casing supporting said driven member for rotation about said axis; a rotary driving member in the casing supported upon the shaft for relative rotation with respect thereto; means for axially moving the driving member with respect to the shaft in accordance with the relative angular movement therebetween, comprising means forming a pair of axially spaced peripheral grooves on said shaft, each groove being in the form of a closed loop the grooves being equally oblique to the said axis and symmetrically oriented with respect to a plane normal to said axis, and ball detents carried by the driving member extending respectively into the grooves, the ball detents being axially spaced from each other in an amount corresponding to the axial spacing of the grooves, the ball detents being located on diametrically opposite sides of said axis, the detents being capable of simultaneously engaging respectively those portions of the grooves located nearest the driven member to determine a limite axially advanced position of said driving member; means forming a coupling between the members separable upon a predetermined axial retraction of said driving member from said axially advanced position, comprising abutments carried respectively by the members; a helical compression spring extending about the driving member and engaging at opposite ends, said bearing means and said driving member for urging the driving member toward said axially advanced position; and a pin detachably carried by the said end of said shaft limiting axial movement of said shaft under the influence of said compression spring.

References Cited in the file of this patent UNiTED STATES PATENTS 1,657,274 Niedhammer Jan. 24, i928 1,776,057 Weibull Sept. 16, 1930 2,160,150 Jimerson et a1. May 30, 1939 2,219,865 Fitch Oct. 29, 1940 2,492,840 Bugg Dec. 27, 1949 2,539,678 Thomas Ian. 30, 1951 2,583,147 Kaplan Jan. 22, 1952 

